1. The intensity of sound during a normal conversation usually falls within the range of 50 to 60 decibels. This sound level is considered moderate and is typical of everyday human interactions where people speak at a comfortable volume. The decibel scale, which measures sound intensity, shows that thiRead more

    The intensity of sound during a normal conversation usually falls within the range of 50 to 60 decibels. This sound level is considered moderate and is typical of everyday human interactions where people speak at a comfortable volume. The decibel scale, which measures sound intensity, shows that this range is neither too quiet nor excessively loud, making it ideal for clear communication without causing discomfort. In comparison, whispering is around 20-30 decibels, while shouting can exceed 70 decibels. Understanding this range is important for designing spaces like offices, classrooms, and public areas to ensure they support effective communication without contributing to noise pollution. Hence, the correct answer is [C] 50-60 decibels.

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  2. Sound or noise pollution is measured in decibels (dB), a unit used to quantify the intensity of sound. Decibels provide a logarithmic scale that corresponds to the human ear's perception of sound levels, making it suitable for measuring both very soft and very loud sounds. The decibel scale is usedRead more

    Sound or noise pollution is measured in decibels (dB), a unit used to quantify the intensity of sound. Decibels provide a logarithmic scale that corresponds to the human ear’s perception of sound levels, making it suitable for measuring both very soft and very loud sounds. The decibel scale is used to express a wide range of sound pressures, from the faintest sound the human ear can detect (0 dB) to levels that can cause immediate harm (above 120 dB). Noise pollution, which refers to harmful or excessive levels of noise in the environment, is assessed using decibels to determine its impact on human health and well-being. This measurement is crucial for regulating noise levels in various settings, such as urban areas, workplaces, and transportation systems. Hence, the correct answer is [C] Decibel.

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  3. Mach numbers are used primarily in relation to the velocity of objects moving through a fluid, such as air, and are most commonly applied to aircraft. The Mach number represents the ratio of an object's speed to the speed of sound in the same medium. For example, an aircraft traveling at Mach 1 moveRead more

    Mach numbers are used primarily in relation to the velocity of objects moving through a fluid, such as air, and are most commonly applied to aircraft. The Mach number represents the ratio of an object’s speed to the speed of sound in the same medium. For example, an aircraft traveling at Mach 1 moves at the speed of sound, while at Mach 2, it travels twice as fast as sound. This concept is crucial in aerodynamics, influencing the design, performance, and behavior of aircraft, particularly at high speeds where compressibility effects and shock waves become significant. While Mach numbers can also apply to other high-speed vehicles like spacecraft, their primary and most frequent use is in the context of aircraft. Therefore, the correct answer is [C] Aircraft.

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  4. The ratio of an object's velocity to the velocity of sound in the same medium and under the same conditions is called the Mach number. Named after physicist Ernst Mach, it is a dimensionless quantity that represents the object's speed relative to the speed of sound. For instance, an aircraft traveliRead more

    The ratio of an object’s velocity to the velocity of sound in the same medium and under the same conditions is called the Mach number. Named after physicist Ernst Mach, it is a dimensionless quantity that represents the object’s speed relative to the speed of sound. For instance, an aircraft traveling at Mach 2 moves at twice the speed of sound. This concept is essential in aerodynamics and fluid mechanics, influencing the study and design of high-speed vehicles such as aircraft and spacecraft. The Mach number determines the flow regime: subsonic (Mach 1), and hypersonic (Mach > 5). It affects airflow behavior, shock waves, and compressibility effects, making it a crucial parameter for engineers and scientists working on high-speed travel and technologies. Hence, the correct answer is [D] Mach number.

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  5. If the horse starts moving suddenly, the possibility of the rider falling is due to inertia. Inertia is the property of matter that resists changes in motion. When the horse accelerates forward, the rider tends to remain at rest due to their inertia. This causes the rider to lean backward or lose baRead more

    If the horse starts moving suddenly, the possibility of the rider falling is due to inertia. Inertia is the property of matter that resists changes in motion. When the horse accelerates forward, the rider tends to remain at rest due to their inertia. This causes the rider to lean backward or lose balance, potentially leading to a fall. This phenomenon aligns with Newton’s first law of motion, often referred to as the law of inertia. According to this law, an object at rest will remain at rest unless acted upon by an external force. In this scenario, the sudden motion of the horse acts as the external force, causing the rider to experience a change in motion. Therefore, the possibility of the rider falling when the horse starts moving suddenly can be attributed to the principle of inertia described by Newton’s first law of motion.

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